From 9feec51e2dd754819e5c730ac5985d28d57adb48 Mon Sep 17 00:00:00 2001 From: Lewis Marshall Date: Mon, 25 Sep 2017 09:08:07 +0100 Subject: p2p: add network simulation framework (#14982) This commit introduces a network simulation framework which can be used to run simulated networks of devp2p nodes. The intention is to use this for testing protocols, performing benchmarks and visualising emergent network behaviour. --- vendor/github.com/julienschmidt/httprouter/tree.go | 656 +++++++++++++++++++++ 1 file changed, 656 insertions(+) create mode 100644 vendor/github.com/julienschmidt/httprouter/tree.go (limited to 'vendor/github.com/julienschmidt/httprouter/tree.go') diff --git a/vendor/github.com/julienschmidt/httprouter/tree.go b/vendor/github.com/julienschmidt/httprouter/tree.go new file mode 100644 index 000000000..a8fa98b04 --- /dev/null +++ b/vendor/github.com/julienschmidt/httprouter/tree.go @@ -0,0 +1,656 @@ +// Copyright 2013 Julien Schmidt. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be found +// in the LICENSE file. + +package httprouter + +import ( + "strings" + "unicode" + "unicode/utf8" +) + +func min(a, b int) int { + if a <= b { + return a + } + return b +} + +func countParams(path string) uint8 { + var n uint + for i := 0; i < len(path); i++ { + if path[i] != ':' && path[i] != '*' { + continue + } + n++ + } + if n >= 255 { + return 255 + } + return uint8(n) +} + +type nodeType uint8 + +const ( + static nodeType = iota // default + root + param + catchAll +) + +type node struct { + path string + wildChild bool + nType nodeType + maxParams uint8 + indices string + children []*node + handle Handle + priority uint32 +} + +// increments priority of the given child and reorders if necessary +func (n *node) incrementChildPrio(pos int) int { + n.children[pos].priority++ + prio := n.children[pos].priority + + // adjust position (move to front) + newPos := pos + for newPos > 0 && n.children[newPos-1].priority < prio { + // swap node positions + n.children[newPos-1], n.children[newPos] = n.children[newPos], n.children[newPos-1] + + newPos-- + } + + // build new index char string + if newPos != pos { + n.indices = n.indices[:newPos] + // unchanged prefix, might be empty + n.indices[pos:pos+1] + // the index char we move + n.indices[newPos:pos] + n.indices[pos+1:] // rest without char at 'pos' + } + + return newPos +} + +// addRoute adds a node with the given handle to the path. +// Not concurrency-safe! +func (n *node) addRoute(path string, handle Handle) { + fullPath := path + n.priority++ + numParams := countParams(path) + + // non-empty tree + if len(n.path) > 0 || len(n.children) > 0 { + walk: + for { + // Update maxParams of the current node + if numParams > n.maxParams { + n.maxParams = numParams + } + + // Find the longest common prefix. + // This also implies that the common prefix contains no ':' or '*' + // since the existing key can't contain those chars. + i := 0 + max := min(len(path), len(n.path)) + for i < max && path[i] == n.path[i] { + i++ + } + + // Split edge + if i < len(n.path) { + child := node{ + path: n.path[i:], + wildChild: n.wildChild, + nType: static, + indices: n.indices, + children: n.children, + handle: n.handle, + priority: n.priority - 1, + } + + // Update maxParams (max of all children) + for i := range child.children { + if child.children[i].maxParams > child.maxParams { + child.maxParams = child.children[i].maxParams + } + } + + n.children = []*node{&child} + // []byte for proper unicode char conversion, see #65 + n.indices = string([]byte{n.path[i]}) + n.path = path[:i] + n.handle = nil + n.wildChild = false + } + + // Make new node a child of this node + if i < len(path) { + path = path[i:] + + if n.wildChild { + n = n.children[0] + n.priority++ + + // Update maxParams of the child node + if numParams > n.maxParams { + n.maxParams = numParams + } + numParams-- + + // Check if the wildcard matches + if len(path) >= len(n.path) && n.path == path[:len(n.path)] && + // Check for longer wildcard, e.g. :name and :names + (len(n.path) >= len(path) || path[len(n.path)] == '/') { + continue walk + } else { + // Wildcard conflict + var pathSeg string + if n.nType == catchAll { + pathSeg = path + } else { + pathSeg = strings.SplitN(path, "/", 2)[0] + } + prefix := fullPath[:strings.Index(fullPath, pathSeg)] + n.path + panic("'" + pathSeg + + "' in new path '" + fullPath + + "' conflicts with existing wildcard '" + n.path + + "' in existing prefix '" + prefix + + "'") + } + } + + c := path[0] + + // slash after param + if n.nType == param && c == '/' && len(n.children) == 1 { + n = n.children[0] + n.priority++ + continue walk + } + + // Check if a child with the next path byte exists + for i := 0; i < len(n.indices); i++ { + if c == n.indices[i] { + i = n.incrementChildPrio(i) + n = n.children[i] + continue walk + } + } + + // Otherwise insert it + if c != ':' && c != '*' { + // []byte for proper unicode char conversion, see #65 + n.indices += string([]byte{c}) + child := &node{ + maxParams: numParams, + } + n.children = append(n.children, child) + n.incrementChildPrio(len(n.indices) - 1) + n = child + } + n.insertChild(numParams, path, fullPath, handle) + return + + } else if i == len(path) { // Make node a (in-path) leaf + if n.handle != nil { + panic("a handle is already registered for path '" + fullPath + "'") + } + n.handle = handle + } + return + } + } else { // Empty tree + n.insertChild(numParams, path, fullPath, handle) + n.nType = root + } +} + +func (n *node) insertChild(numParams uint8, path, fullPath string, handle Handle) { + var offset int // already handled bytes of the path + + // find prefix until first wildcard (beginning with ':'' or '*'') + for i, max := 0, len(path); numParams > 0; i++ { + c := path[i] + if c != ':' && c != '*' { + continue + } + + // find wildcard end (either '/' or path end) + end := i + 1 + for end < max && path[end] != '/' { + switch path[end] { + // the wildcard name must not contain ':' and '*' + case ':', '*': + panic("only one wildcard per path segment is allowed, has: '" + + path[i:] + "' in path '" + fullPath + "'") + default: + end++ + } + } + + // check if this Node existing children which would be + // unreachable if we insert the wildcard here + if len(n.children) > 0 { + panic("wildcard route '" + path[i:end] + + "' conflicts with existing children in path '" + fullPath + "'") + } + + // check if the wildcard has a name + if end-i < 2 { + panic("wildcards must be named with a non-empty name in path '" + fullPath + "'") + } + + if c == ':' { // param + // split path at the beginning of the wildcard + if i > 0 { + n.path = path[offset:i] + offset = i + } + + child := &node{ + nType: param, + maxParams: numParams, + } + n.children = []*node{child} + n.wildChild = true + n = child + n.priority++ + numParams-- + + // if the path doesn't end with the wildcard, then there + // will be another non-wildcard subpath starting with '/' + if end < max { + n.path = path[offset:end] + offset = end + + child := &node{ + maxParams: numParams, + priority: 1, + } + n.children = []*node{child} + n = child + } + + } else { // catchAll + if end != max || numParams > 1 { + panic("catch-all routes are only allowed at the end of the path in path '" + fullPath + "'") + } + + if len(n.path) > 0 && n.path[len(n.path)-1] == '/' { + panic("catch-all conflicts with existing handle for the path segment root in path '" + fullPath + "'") + } + + // currently fixed width 1 for '/' + i-- + if path[i] != '/' { + panic("no / before catch-all in path '" + fullPath + "'") + } + + n.path = path[offset:i] + + // first node: catchAll node with empty path + child := &node{ + wildChild: true, + nType: catchAll, + maxParams: 1, + } + n.children = []*node{child} + n.indices = string(path[i]) + n = child + n.priority++ + + // second node: node holding the variable + child = &node{ + path: path[i:], + nType: catchAll, + maxParams: 1, + handle: handle, + priority: 1, + } + n.children = []*node{child} + + return + } + } + + // insert remaining path part and handle to the leaf + n.path = path[offset:] + n.handle = handle +} + +// Returns the handle registered with the given path (key). The values of +// wildcards are saved to a map. +// If no handle can be found, a TSR (trailing slash redirect) recommendation is +// made if a handle exists with an extra (without the) trailing slash for the +// given path. +func (n *node) getValue(path string) (handle Handle, p Params, tsr bool) { +walk: // outer loop for walking the tree + for { + if len(path) > len(n.path) { + if path[:len(n.path)] == n.path { + path = path[len(n.path):] + // If this node does not have a wildcard (param or catchAll) + // child, we can just look up the next child node and continue + // to walk down the tree + if !n.wildChild { + c := path[0] + for i := 0; i < len(n.indices); i++ { + if c == n.indices[i] { + n = n.children[i] + continue walk + } + } + + // Nothing found. + // We can recommend to redirect to the same URL without a + // trailing slash if a leaf exists for that path. + tsr = (path == "/" && n.handle != nil) + return + + } + + // handle wildcard child + n = n.children[0] + switch n.nType { + case param: + // find param end (either '/' or path end) + end := 0 + for end < len(path) && path[end] != '/' { + end++ + } + + // save param value + if p == nil { + // lazy allocation + p = make(Params, 0, n.maxParams) + } + i := len(p) + p = p[:i+1] // expand slice within preallocated capacity + p[i].Key = n.path[1:] + p[i].Value = path[:end] + + // we need to go deeper! + if end < len(path) { + if len(n.children) > 0 { + path = path[end:] + n = n.children[0] + continue walk + } + + // ... but we can't + tsr = (len(path) == end+1) + return + } + + if handle = n.handle; handle != nil { + return + } else if len(n.children) == 1 { + // No handle found. Check if a handle for this path + a + // trailing slash exists for TSR recommendation + n = n.children[0] + tsr = (n.path == "/" && n.handle != nil) + } + + return + + case catchAll: + // save param value + if p == nil { + // lazy allocation + p = make(Params, 0, n.maxParams) + } + i := len(p) + p = p[:i+1] // expand slice within preallocated capacity + p[i].Key = n.path[2:] + p[i].Value = path + + handle = n.handle + return + + default: + panic("invalid node type") + } + } + } else if path == n.path { + // We should have reached the node containing the handle. + // Check if this node has a handle registered. + if handle = n.handle; handle != nil { + return + } + + if path == "/" && n.wildChild && n.nType != root { + tsr = true + return + } + + // No handle found. Check if a handle for this path + a + // trailing slash exists for trailing slash recommendation + for i := 0; i < len(n.indices); i++ { + if n.indices[i] == '/' { + n = n.children[i] + tsr = (len(n.path) == 1 && n.handle != nil) || + (n.nType == catchAll && n.children[0].handle != nil) + return + } + } + + return + } + + // Nothing found. We can recommend to redirect to the same URL with an + // extra trailing slash if a leaf exists for that path + tsr = (path == "/") || + (len(n.path) == len(path)+1 && n.path[len(path)] == '/' && + path == n.path[:len(n.path)-1] && n.handle != nil) + return + } +} + +// Makes a case-insensitive lookup of the given path and tries to find a handler. +// It can optionally also fix trailing slashes. +// It returns the case-corrected path and a bool indicating whether the lookup +// was successful. +func (n *node) findCaseInsensitivePath(path string, fixTrailingSlash bool) (ciPath []byte, found bool) { + return n.findCaseInsensitivePathRec( + path, + strings.ToLower(path), + make([]byte, 0, len(path)+1), // preallocate enough memory for new path + [4]byte{}, // empty rune buffer + fixTrailingSlash, + ) +} + +// shift bytes in array by n bytes left +func shiftNRuneBytes(rb [4]byte, n int) [4]byte { + switch n { + case 0: + return rb + case 1: + return [4]byte{rb[1], rb[2], rb[3], 0} + case 2: + return [4]byte{rb[2], rb[3]} + case 3: + return [4]byte{rb[3]} + default: + return [4]byte{} + } +} + +// recursive case-insensitive lookup function used by n.findCaseInsensitivePath +func (n *node) findCaseInsensitivePathRec(path, loPath string, ciPath []byte, rb [4]byte, fixTrailingSlash bool) ([]byte, bool) { + loNPath := strings.ToLower(n.path) + +walk: // outer loop for walking the tree + for len(loPath) >= len(loNPath) && (len(loNPath) == 0 || loPath[1:len(loNPath)] == loNPath[1:]) { + // add common path to result + ciPath = append(ciPath, n.path...) + + if path = path[len(n.path):]; len(path) > 0 { + loOld := loPath + loPath = loPath[len(loNPath):] + + // If this node does not have a wildcard (param or catchAll) child, + // we can just look up the next child node and continue to walk down + // the tree + if !n.wildChild { + // skip rune bytes already processed + rb = shiftNRuneBytes(rb, len(loNPath)) + + if rb[0] != 0 { + // old rune not finished + for i := 0; i < len(n.indices); i++ { + if n.indices[i] == rb[0] { + // continue with child node + n = n.children[i] + loNPath = strings.ToLower(n.path) + continue walk + } + } + } else { + // process a new rune + var rv rune + + // find rune start + // runes are up to 4 byte long, + // -4 would definitely be another rune + var off int + for max := min(len(loNPath), 3); off < max; off++ { + if i := len(loNPath) - off; utf8.RuneStart(loOld[i]) { + // read rune from cached lowercase path + rv, _ = utf8.DecodeRuneInString(loOld[i:]) + break + } + } + + // calculate lowercase bytes of current rune + utf8.EncodeRune(rb[:], rv) + // skipp already processed bytes + rb = shiftNRuneBytes(rb, off) + + for i := 0; i < len(n.indices); i++ { + // lowercase matches + if n.indices[i] == rb[0] { + // must use a recursive approach since both the + // uppercase byte and the lowercase byte might exist + // as an index + if out, found := n.children[i].findCaseInsensitivePathRec( + path, loPath, ciPath, rb, fixTrailingSlash, + ); found { + return out, true + } + break + } + } + + // same for uppercase rune, if it differs + if up := unicode.ToUpper(rv); up != rv { + utf8.EncodeRune(rb[:], up) + rb = shiftNRuneBytes(rb, off) + + for i := 0; i < len(n.indices); i++ { + // uppercase matches + if n.indices[i] == rb[0] { + // continue with child node + n = n.children[i] + loNPath = strings.ToLower(n.path) + continue walk + } + } + } + } + + // Nothing found. We can recommend to redirect to the same URL + // without a trailing slash if a leaf exists for that path + return ciPath, (fixTrailingSlash && path == "/" && n.handle != nil) + } + + n = n.children[0] + switch n.nType { + case param: + // find param end (either '/' or path end) + k := 0 + for k < len(path) && path[k] != '/' { + k++ + } + + // add param value to case insensitive path + ciPath = append(ciPath, path[:k]...) + + // we need to go deeper! + if k < len(path) { + if len(n.children) > 0 { + // continue with child node + n = n.children[0] + loNPath = strings.ToLower(n.path) + loPath = loPath[k:] + path = path[k:] + continue + } + + // ... but we can't + if fixTrailingSlash && len(path) == k+1 { + return ciPath, true + } + return ciPath, false + } + + if n.handle != nil { + return ciPath, true + } else if fixTrailingSlash && len(n.children) == 1 { + // No handle found. Check if a handle for this path + a + // trailing slash exists + n = n.children[0] + if n.path == "/" && n.handle != nil { + return append(ciPath, '/'), true + } + } + return ciPath, false + + case catchAll: + return append(ciPath, path...), true + + default: + panic("invalid node type") + } + } else { + // We should have reached the node containing the handle. + // Check if this node has a handle registered. + if n.handle != nil { + return ciPath, true + } + + // No handle found. + // Try to fix the path by adding a trailing slash + if fixTrailingSlash { + for i := 0; i < len(n.indices); i++ { + if n.indices[i] == '/' { + n = n.children[i] + if (len(n.path) == 1 && n.handle != nil) || + (n.nType == catchAll && n.children[0].handle != nil) { + return append(ciPath, '/'), true + } + return ciPath, false + } + } + } + return ciPath, false + } + } + + // Nothing found. + // Try to fix the path by adding / removing a trailing slash + if fixTrailingSlash { + if path == "/" { + return ciPath, true + } + if len(loPath)+1 == len(loNPath) && loNPath[len(loPath)] == '/' && + loPath[1:] == loNPath[1:len(loPath)] && n.handle != nil { + return append(ciPath, n.path...), true + } + } + return ciPath, false +} -- cgit v1.2.3